In most fuel supply systems applicable to internal combustion engines, fuel injectors are used to direct fuel pulses into the engine combustion chamber. A commonly used injector is a closed-nozzle injector which includes a nozzle assembly having a spring-biased nozzle valve element positioned adjacent the nozzle orifice for resisting blow back of exhaust gas into the pumping or metering chamber of the injector while allowing fuel to be injected into the engine cylinder. The nozzle valve element also functions to provide a deliberate, abrupt end to fuel injection thereby preventing a secondary injection which causes unburned hydrocarbons in the exhaust. The nozzle valve is positioned in a nozzle cavity and biased by a nozzle spring to block fuel flow through the nozzle orifices. In many fuel systems, when the pressure of the fuel within the nozzle cavity exceeds the biasing force of the nozzle spring, the nozzle valve element moves outwardly to allow fuel to pass through the nozzle orifices, thus marking the beginning of injection.
Furthermore, fuel injectors have been commonly used with internal combustion engines such as diesel engines to deliver combustible fuel to the combustion chambers within the cylinders of the engine. Various injector designs have been implemented in the art but most fuel injectors have a nozzle with a valve element movably disposed therein which when opened, provides a spray of fuel into the combustion chamber of the cylinder. In this regard, fuel injectors typically include a nozzle including an outer barrel, a retainer, an injector seal and an injector nozzle housing that houses the valve element of the fuel injector. The fuel injector is typically mounted in an injector bore in the cylinder head of the internal combustion engine with the nozzle orifices generally extending at least partially into the combustion chamber so that fuel may be provided therethrough. In this regard, the retainer and the injector seal are received within the injector bores of the cylinder head and includes an opening proximate to the combustion chamber of the engine cylinder which allows the nozzle housing to extend into the combustion chamber. The injector seal is positioned around the injector nozzle and compressed between the nozzle and the cylinder head within the bore, thereby effectively sealing or inhibiting any expanding gases from escaping through the injector bore of the cylinder head from the combustion chamber during engine operation.
The injector seal may be configured as a circular ring to slide axially on an injector nozzle housing having an outer diameter until the injector seal attains an interference fit on the injector nozzle housing outer diameter. The interference fit is predetermined by the dimensions at a location on the injector nozzle housing outer diameter that is preferably proximate a cylinder head sealing face and an injector sealing face in order to, in effect, clamp or sandwich the injector seal between the sealing faces upon assembly. The use of an interference fit has not been an effective method to capture the injector seal. For instance, if the injector seal shifts or is moved from the predetermined interference fit location on the injector nozzle housing outer diameter, the injector seal may fall off the injector nozzle housing or get stuck within the injector bore itself upon removal of the fuel injector from the bore during disassembly.
However, there still exists a need for an improved fuel injector assembly with an injector seal retention having a nozzle and injector seal combination with improved injector seal retention. In particular, there exists an unfulfilled need for such a nozzle that will more securely capture the injector seal during installation and/or removal of a fuel injector into and from an engine cylinder head or injector bore. In this regard, there is a need for such a nozzle configuration which securely captures the injector seal, thereby preventing the injector seal from being lost, avoiding any inadvertent disengagement of the injector seal from the injector nozzle housing, and/or the injector seal remaining within the injector bore upon removal of the fuel injector making seal removal difficult, time consuming and costly. Further, a configuration to properly capture the injector seal may result in minimizing misalignment of the injector nozzle during assembly
Accordingly, it is desirable to provide a method and apparatus that will capture the injector seal on the injector nozzle housing even during installation and/or removal of the fuel injector.